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2011
The visible surface of the Sun is a layer called the photosphere. This layer is a thin shell of hot, ionised gases or plasma about 400 km thick. Most of the energy radiated by the Sun passes through this layer. From Earth, the surface looks smooth, but it is actually turbulent and granular because of convection currents.
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The visible surface of the Sun is a layer called the photosphere. This layer is a thin shell of hot, ionised gases or plasma about 400 km thick. Most of the energy radiated by the Sun passes through this layer. From Earth, the surface looks smooth, but it is actually turbulent and granular because of convection currents.
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Narrowcasting for Stereoscopic Photospherical Cinemagraphy
2019Demo
Michael Cohen 0002 +2 more
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Photospheric Variability of O Stars
Astrophysics and Space Science, 1994The characteristics of the line profile variations observed in optical transitions of O-type stars are reviewed. For a few well-observed stars, there is compelling evidence that the variations are due to photospheric velocity fields from one or more modes of nonradial pulsation.
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2019
Recent debates about the accuracy of measuring the solar radius attribute an uncertainty (including systematic errors) of about σR ± 500 km (e.g., Emilio et al. 2012), which amounts to a relative accuracy of σR∕R ≈ 0.0007. Space-based observations are considered to be more accurate than ground-based measurements, which are impacted by the seeing ...
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Recent debates about the accuracy of measuring the solar radius attribute an uncertainty (including systematic errors) of about σR ± 500 km (e.g., Emilio et al. 2012), which amounts to a relative accuracy of σR∕R ≈ 0.0007. Space-based observations are considered to be more accurate than ground-based measurements, which are impacted by the seeing ...
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1965
The sun has a radius R = 7 × 105 km, and is situated about rE = 1.5 × 108 km from the earth. Since the mass of the sun is M= 2 × 1033 g the average density can be determined as 1.4 gcm-3. However, the density changes from 70 gem-3 at the solar centre, where the temperature is 14 × 106 °K, to 10-7 gem-3 in the photosphere.
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The sun has a radius R = 7 × 105 km, and is situated about rE = 1.5 × 108 km from the earth. Since the mass of the sun is M= 2 × 1033 g the average density can be determined as 1.4 gcm-3. However, the density changes from 70 gem-3 at the solar centre, where the temperature is 14 × 106 °K, to 10-7 gem-3 in the photosphere.
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Photospheric Vortices and Coronal Heating
International Astronomical Union Colloquium, 1993AbstractWe have used the results of a realistic simulation of convection to estimate the power input to coronal loops from the twisting of photospheric magnetic field in intergranular vortices. In this simulation, the vorticity is large (a mean of 0.03 s–1) nearly everywhere in the intergranular lanes, not merely at the corners of three granules.
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On the Effective Temperatures of Extended Photospheres
Mathematical Proceedings of the Cambridge Philosophical Society, 1935For material stratified in parallel planes in local thermodynamical equilibrium we have Milne's well-known result thatwhere πF is the constant net integrated flux of radiation, τ is the optical depth and B is the “ergiebigkeit” which is related to the temperature T by the relationσ being the Stefan-Boltzmann constant.
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Magnetic fields in the solar photosphere
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2008Recent high-resolution observations of the surface of the Sun have revealed the fine structure of a vast array of complex photospheric magnetic features. Observations of these magnetic field structures have already greatly enhanced our theoretical understanding of the interactions between magnetic fields and turbulent convection, and future ...
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